Tunable E ect of the Calcination of the Silanol Groups of KIT-6 and SBA-15 Mesoporous Materials

Abstract

The calcination process is a crucial step during SBA-15 and KIT-6 synthesis. It is used to completely remove the organic template and condense silanol groups, and it allows the determination of the textural and physical properties of these materials, depending on the adopted conditions. Moreover, calcination influences the number of silanols available on the surface of the material. The concentration of silanols is important if these materials were synthesized for use in adsorption or functionalization. To understand and optimize the silanol groups of SBA-15 and KIT-6, in this study, the temperature and time calcination parameters were varied. The experiments were performed at 300, 400, and 500 C for 300, 400, and 500 min. The results show that the ideal temperature to preserve the silanol groups is 300 C, but to optimize the textural properties, it is better to calcine these molecular sieves at 400 C. A calcination for 10 h did not give better results than a calcination for 5 h, demonstrating that the former duration is excessive for use.